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White-Rogers Thermostat - Heat Won't Shut Off

Hello,

I just moved into a new house last week and I'm having an issue with the upstairs thermostat. I'm a first time home owner and looking for some guidance on how to troubleshoot the problem. An explanation of the issue is below.

We have two heat pumps and two thermostats - one for downstairs and one for upstairs. The downstairs unit works great but the issue is with the upstairs thermostat.

The heat was working fine for the first two days, but when I came home from work on Friday I went upstairs and noticed it was stifling hot. The thermostat was set at 60 but the room temperature was 90 and was continuously blowing out of the vents upstairs. So the heat must have been blowing all day and it never shut off when it reached the desired temperature. The settings on the thermostat were at Auto Fan and Heat, which are the correct settings to my knowledge.

To get around the problem, I just turned off the upstairs unit and it did shut off for me. However, the same thing happened the next day when I turned it on again - the heat kept running after reaching the desired temp...in excess of 15 degrees. This time, however, the heat would not shut off when switched to the "off" position. I left it go for about an hour and tried it again and it then finally did shut off.

I am now afraid to turn it back on because I'm worried I will not be able to shut it off.

Here are the specs on the thermostat

white-rogers comfort-set standard 1F89-211 pro-spec #80h∅w

Any advice that can point me in the right direction would be a huge help. Thank you!

My best guess would be that its a stuck on relay for the emergency, or axillary heat. Thermostats are usually not the problem, but it could be. Was the outdoor unit running when you experienced the stuck on heat problem?

As iron sharpens iron so one man sharpens another Proverbs 27:17 NIV84

My best guess would be that its a stuck on relay for the emergency, or axillary heat. Thermostats are usually not the problem, but it could be. Was the outdoor unit running when you experienced the stuck on heat problem?

That's a good question, but I can't give you a definite answer. I want to say it was, but I didn't go outside to check at the time so I can't say for sure. I checked the outdoor unit after the heat went off to see if there was anything that stood out. The only thing I noticed was that there was ice around the cords that go from the unit to the house - not sure if that can have an effect though or not?

If I want to turn on the heat again upstairs to test out the system and it doesn't shut off, is it okay to use the breaker as a last resort? I wasn't sure if that would damage the system by suddenly shutting off the power to it.

Now it sounds like there is a low voltage short because you say there was ice on the pipes. That means it was in the a/c mode of operation. It could be the thermostat, now that you say that there was ice on the pipes. It could be a low voltage short. Sounds like you need a professional to diagnose system.

And yes, it is okay to shut those breakers off.

As iron sharpens iron so one man sharpens another Proverbs 27:17 NIV84

Now it sounds like there is a low voltage short because you say there was ice on the pipes. That means it was in the a/c mode of operation. It could be the thermostat, now that you say that there was ice on the pipes. It could be a low voltage short. Sounds like you need a professional to diagnose system.

And yes, it is okay to shut those breakers off.

Well I should clarify that it did just snow here (Eastern PA) so the ice was probably from the weather. I just didn't know if having ice on those pipes would disrupt how the unit operates.

Regardless, sounds like I should have someone come look at it since the issue is uncertain. Thank you for your input, much appreciated!